1. Field of Invention
This invention relates to a continuously variable transmission (CVT) that utilizes an adjustable fulcrum to vary the output to input ratio instead of gears or frictional means such as belt or toroidal systems.
2. Description of the Related Art
Existing use of automatic or manual transmissions consists of varied combinations of gears, bands, and clutches to produce a predefined number of fixed gear ratios. Many of these types of transmissions, especially automatics, are heavy, complex, and expensive—while also lacking in efficiency due to the limited fixed gear ratios. In contrast, the emerging continuously variable transmission technology offers a wide range of infinite speed and torque ratios, while increasing fuel efficiency and reducing weight, complexity, and costs. Estimates indicate that the new technology will be able to increase fuel efficiency by as much as two miles per gallon and reduce the number of transmission parts required by over 40 percent. Such a reduction in overall costs should create a tremendous future market for this growing technology.
These new transmission types have improved to the point where most of the major automobile manufacturers are currently offering limited options to customers who want an automobile utilizing this advanced technology. Types of continuously variable transmissions that are offered vary, but consist primarily of versions of the belt and pulley or toroidal types. Although improvements have been made in these types of friction systems to accommodate larger torque requirements, they likely will require additional significant improvements before they are generally accepted by automobile owners as preferred and practical transmission systems.
The belt and pulley type transmission works on the principle of a fixed length belt connecting sloped surface input and output pulleys with variably controlled groove widths. As the groove width in the drive pulley decreases, the belt on that pulley is forced toward the outside circumference of the pulley. At the same time the output pulley is increased in width in an amount that will keep the belt tight while allowing the belt on that pulley to move toward the center circumference of the pulley—thus the combined actions result in an increase in output speed. Opposite actions on the same pulleys will result in a decrease in output speed—thus providing continuously variable speed and torque ratios.
The belt and pulley principle might appear to be ideal, but because the belt must be very strong and grip to the pulleys very tightly, this type of transmission has not proven highly practical, especially in high torque applications.
The toroidal type CVT involves two metal disks facing each other—one a drive disk and the other an output disk. Two idler wheels are inserted between the disks—one on each side of the input shaft. These idler wheels are made and controlled so that they can be set at an angle that will allow one side of the idler wheel to run closer to the center of one disk while at the same time allowing the other side of the same wheel to run closer to the outside of the opposing disk, or vice versa—thus variably controlling the speed ratio of the output disk.
Many more patents have been issued on non-belt type transmissions than for belt types, but many of these face some of the same problems encounter by the belt types—mainly slippage, component wear, reliability, and limited torque capability.
Although many of the previously patented continuously variable transmissions offer many interesting and varied approaches to solving this complex problem of variable torque conversion, I believe the approach demonstrated by this invention, even if not ever implemented as proposed, offers a completely new avenue for research and discovery. While all gear boxes operate to some extent on the leverage principle, reasonable research failed to identify any previous CVT patents using a circular eccentric cam, torque converter shaft, and adjustable fulcrum to create a variable vertical “seesaw” action in the torque converter shaft that is then converted into rotary output motion by a unidirectional roller clutch.